Configuration of the custom content type selection size

[felipe]

Hello,
I've developed a custom model under the repository.
This model is configured under the webclient too (custom type selection, custom properties…).
The problem is the custom content type listbox size that is boundered 10.
Is there a solution to confiugure that list in order to have 20 choice, for example.

Thanks

[felipe]

Sorry, I've done an error.
There is more than 10 choices allowed so!